A rope access technology is beginning to spread in which an operator accesses a high place, such as a bridge and a high-rise building where it is difficult to construct a scaffold from the ground, by using a rope and performs an operation such as maintenance and inspection. In the rope access technology, basically, the operator descends from the highest point and accesses an operation site and, after operation, ascends to return to the highest point. An access rope is suspended from a support point secured at the highest point. The operator wearing a harness connects a descender engaged with the access rope to the harness by a carabiner-equipped rope sling. The operator descends gradually while operating the descender, and accesses the operation site. When returning, the operator connects an ascender engaged with the access rope to the harness by the carabiner-equipped rope sling, and ascends gradually while operating the ascender, thereby returning to the support point.
According to the conventional ascender, since the operator is required to ascend by human power, the operator is required a lot of labor.